Quote #5

"With them indeed is fulfilled the prophecy of Isaiah that says: 'You will indeed listen, but never understand, and you will indeed look, but never perceive. For this people's heart has grown dull, and their ears are hard of hearing, and they have shut their eyes; so that they might not look with their eyes, and listen with their ears, and understand with their heart and turn - and I would heal them.'" (NRSV 13:14-15)

And in them is fulfilled the prophecy of Esaias, which saith, By hearing ye shall hear, and shall not understand; and seeing ye shall see, and shall not perceive: For this people's heart is waxed gross, and their ears are dull of hearing, and their eyes they have closed; lest at any time they should see with their eyes and hear with their ears, and should understand with their heart, and should be converted, and I should heal them. (KJV 13:14-15)

Now we're in Isaiah 6:9-10, and Jesus is explaining why he keeps using those crazy parables to teach the disciples. See, Jesus intentionally speaks in code so that only the special few (i.e., his followers) will understand his message.

Quote #6

"Isaiah prophesied rightly about you when he said: 'This people honors me with their lips, but their hearts are far from me; in vain do they worship me, teaching human precepts as doctrines.'" (NRSV 15:7-9)

Ye hypocrites, well did Esaias prophesy of you, saying, This people draweth nigh unto me with their mouth, and honoureth me with their lips; but their heart is far from me. But in vain they do worship me, teaching for doctrines the commandments of men. (KJV 15:7-9)

Why does Jesus keep referring to this Isaiah guy? Well, he was one of the major Hebrew prophets (prophets = prophecy), so pointing to his words gives Matthew (via Jesus) some major street cred.